ABSTRACT
This chapter explores two advantages of adopting the Two-Set Reading of Rule 3. In the opening section of the chapter, it is shown that Newton aims to persuade his readers that his program of experimental philosophy is consistent with the atomist picture of natural bodies. Building from this image of Newton’s argument strategy, it is demonstrated that on the Two-Set Reading of Rule 3 Newton has adequate grounds to support his claim that inertia should be considered an inherent and essential force, whereas gravity should not. The book concludes by showing that from the Two-Set Reading we gain a more crystallized view of the differences between Newton’s experimental philosophy and Descartes’s hypothetical philosophy. It is argued that insofar as Rule 3 allows the experimental philosopher to regard some universalized qualities as the general but nonessential qualities of bodies, Newton can explain the system of the world in reference to a universal force of gravity that really exists without requiring knowledge of which qualities are essential to natural bodies.
